caif: fix memory leak in cfctrl_linkup_request()

caif: fix memory leak in cfctrl_linkup_request()

When linktype is unknown or kzalloc failed in cfctrl_linkup_request(),
pkt is not released. Add release process to error path.

Fixes: b482cd2053e3 ("net-caif: add CAIF core protocol stack")
Fixes: 8d545c8f958f ("caif: Disconnect without waiting for response")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20230104065146.1153009-1-shaozhengchao@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>